I can see that the postChannel utility is not working as the structure of new channelOodles solver has been changed. Now the R field is not being written.
however I want to compare the stress components across the channel and therefore i need the urms and vrms value of the the velocity. ( I took these urms and vrms terms from postchannel utility declaration). How can we obtain these stress values now?

I again have some doubt about the UPrime2Mean. is this UPrime2Mean is stress-components along xx, yy and zz?? If yes, then what about the stress component in XY direction? (which was termed as "uv" in postChannel utility)

2) I understand that the 6 components will give me the all stresses and I can see those 6 stresses in the file UPrime2Mean. but How to extract/sample the individual component of the stress from the file UPrime2Mean? I tried sample utility but they do not sample UPrime2Mean field. Doing it in excel is another option but isn't there some available method?

1) Do you mean, I should copy those postchannel-utility files and recompile my openfoam solver? Could you please tell me which files you are referring to?

Thanks Daniel
Its been great help for me.
I have done some editing in postChannel utility and I have considered UPrime2Mean and R to be same symmmTensor and replaced R with UPrime2Mean and recompiled the utility. Is it a right thing to do?
see the readField.c and collapse.H file readFields.Hcollapse.H

Another question is:
Is there any recent modification in channelIndex.C file? I can see that you suggested some modification in that file.
Actually, I am getting some ambiguous result when I compare the results for channel flow using postChannel utility (modified by me) and sample utility available with foam. See the attached picture.. the Umean's x-component is plotted where green line is plotted using postchannel utility and red line is plotted with sample utility.

1) Compare version 1.4.1 and 1.5, note their differences, then you will see what R means
2) Don't use UPrime2Mean, but use R to get what you want.
3) Include "calculateAverages.H" from OF-1.4.1 so that you can get R field.

There is definetely some problem here. because I have a openfoam-1.4.1 installed on other system and when I plot the Uf with R field then I found that the same difference in Umean's x-component and Uf (which is also umean's x -component defined in postChannel/collapse.H).
What could be the reason for this difference? Why there is different plot for same variable plot? I might be wrong somewhere in my assumption.

Hi Daniel,
Thnaks for reply. Could you please try to compare your Umean.component(0) profile and Uf profile obtained from postchannel utility?? As per the code, they should be the same.
In case you are busy, then could you please send the tar dir of the channel395 case which provides you good Uf profile?

If any one can please see the problem mention on this forum dated September 04, 2008 and give me some suggestion then it would be of great help.